Document WO 2008/072151 A2 describes a device for imaging a skin object near a skin surface of a body part, comprising a light source and a detector for detecting radiation returning from the object, wherein the device further comprises a linear, elliptical, or preferably circular polarizer between the source and the skin surface. The device also comprises a ratio increaser means for increasing the ratio of radiation coming from the object to radiation coming from the skin surface. The ratio increaser may be an additional or the same elliptical polarizer. Using elliptically or even circularly polarized light makes hair detection independent of the orientation of hair with respect to light direction and polarization, which renders the detection more reliable. The document further describes an imaging method and a hair-shortening device and method.
An entry point in optical shaving technology with a potential to improve closeness of the shaving process comprises the development of an optical shaver, also referred to as shaving device in the following, wherein the shaving device is adapted for cutting a hair at the skin surface or below the skin surface of a human or animal body part or any other body part.
However, it is difficult to detect and localize each hair with a high resolution and ensure that the shaving process is performed only at the desired location, i.e. at the position of a hair and not at the position of the human or animal skin near a human or animal body part, respectively. At the same time, the shaving process must be reliable. Furthermore, the costs for implementing such a shaving process are high and such a shaving device is complex.